1. Technical Field of the Invention
The present invention relates to a method and system for controlling behaviors of a vehicle, especially a running vehicle, based on a plurality of sets of time-dependent data received from various sensors to detect information indicating vehicle behaviors.
2. Description of the Related Art
Various types of systems for controlling behaviors of a vehicle (i.e., various type vehicle control systems) have been known and a vehicle control system that uses a plurality of sets of time-dependent data constitutes one type of those vehicle control systems. For example, such a type of vehicle control system can be realized by a configuration which determines, as a total, information indicative of a crank angle, main throttle opening, and ABS (antilock brake system) ECU (electronic control unit) and then calculates parameters for controlling the brake and engine of the vehicle.
FIG. 1 exemplifies such a control system for vehicles, in which a block diagram of the vehicle control system is provided by a reference 200. This exemplified vehicle control system 200 comprise an engine ECU 220 which receives, from sensors connected to the engine ECU 220, inputs of an idle signal, a crank angle signal, an engine air-intake signal, a main throttle opening signal, a knock signal, an engine cooling water temperature signal, and a starter signal, and transmits some or all data of these received inputs to an integrated ECU 210 via an in-vehicle LAN 250.
In parallel with the data transmission carried out by the engine ECU 220, the ABS ECU 230 receives, from a sensor connected to the ABS ECU 230, an input of a wheel speed signal, and transmits the data of the received input to the integrated ECU 210 via the in-vehicle LAN 250.
Thus it can be said that these engine ECU 220 and ABS ECU 230 transmit time-dependent data, which change consistently depending on running conditions of the vehicle and conditions outside the vehicle.
The integrated ECU 210 receives those time-dependent data transmitted from both of the engine ECU 220 and the ABS ECU 230, and generally uses those received data to calculate parameters for controlling the engine and brake. The control parameters for the engine (i.e., engine control parameters) include an ignition timing of an ignition coil, an amount of fuel to be injected, and timing for fuel injection. The control parameters for the brake (i.e., brake control parameters) include timing for brake and an amount of brake to be operated.
The integrated ECU 210 also transmits the calculated engine and brake control parameters to both the engine ECU 220 and the ABS ECU 230, respectively. The engine ECU 220 uses the engine control parameters transmitted from the integrated ECU 210 as a basis to control actuators, such as an ignition coil, fuel pump, and injector, connected to the engine ECU 220. The ABS ECU 230 uses the brake control parameters transmitted from the integrated ECU 210 as a basis to control a brake actuator connected to the ABS ECU 230.
In the systems for controlling behaviors of vehicles based on a plurality of sets of received time-dependent data as illustrated above, it is desired that the plurality of sets of time-dependent data on which the processing for vehicle behavior control is based have simultaneity. Such a control based on time-dependent data that preferably has simultaneity is made reference as real-time control.
For example, in the above-mentioned example, if the integrated ECU 210 calculates the control parameters using time-dependent data, some of which are transmitted from the engine ECU 220 at time t1 and others of which are transmitted at time t2 that is 1 second after the time t1, these time-dependent data do not exactly reflect the simultaneous conditions to a vehicle and environmental conditions outside the vehicle. If the integrated ECU 210 generally uses such time-dependent data transmitted at different times to calculate the control parameters, mismatching may occur where vehicle behaviors differ largely from that desired in its design.
In actual vehicle control systems that use the foregoing configuration, the in-vehicle LAN 250 may delay the transmission and reception of data due to various reasons (e.g., reasons due to characteristics of communication protocols such as CAN (controller are network) and LIN (local interconnect network)). Thus, even if the integrated ECU 210 uses a plurality of sets of time-dependent data received at mutually-near times to calculate the control parameters and some of the data is delayed in the in-vehicle LAN 250, the mismatching in the vehicle control may really be caused as described above.
Accordingly, in the vehicle control systems, the processing for vehicle behavior control needs to use as a basis a plurality of sets of time-dependent data that reflect the simultaneous conditions in a vehicle and environmental conditions of a vehicle. When such a reflection is met, it is said that the plurality of sets of time-dependent data has simultaneity.